Suppress drag and drop on links on touch screen.

third_party/WebKit/Source/core/input/GestureManager.cpp

Index: third_party/WebKit/Source/core/input/GestureManager.cpp
diff --git a/third_party/WebKit/Source/core/input/GestureManager.cpp b/third_party/WebKit/Source/core/input/GestureManager.cpp
index 8d4d8390eb015b979de2c88dc43261cbc08c0766..4367b8a8a9f9d88d33829c452f5876b5ab8995fd 100644
--- a/third_party/WebKit/Source/core/input/GestureManager.cpp
+++ b/third_party/WebKit/Source/core/input/GestureManager.cpp
@@ -254,14 +254,18 @@ WebInputEventResult GestureManager::handleGestureLongPress(const GestureEventWit
     // supplied HitTestResult), but that will require some overhaul of the touch drag-and-drop code
     // and LongPress is such a special scenario that it's unlikely to matter much in practice.
 
+    IntPoint hitTestPoint = m_frame->view()->rootFrameToContents(gestureEvent.position());
+    HitTestResult hitTestResult = m_frame->eventHandler().hitTestResultAtPoint(hitTestPoint);
+
     m_longTapShouldInvokeContextMenu = false;
-    if (m_frame->eventHandler().handleDragDropIfPossible(targetedEvent)) {
+    bool hitTestContainsLinks = hitTestResult.URLElement() || !hitTestResult.absoluteLinkURL().isNull() || !hitTestResult.absoluteImageURL().isNull() || !hitTestResult.absoluteMediaURL().isNull();

[dcheng, 2016/08/29 19:45:08]

This isn't just links, right? It's images and videos as well?

Alo, why do we needto check URLElement() and absoluteLinkURL().isNull()?

[hush (inactive), 2016/08/29 20:49:49]

Yes. Long pressing on images and videos should open context menu as well,
instead of staring DnD. Otherwise, the user can't open context menu on these
things any more.

We need to check URLElement() and absoluteLinkURL().isNull() because they are
only for links, both URLElement() and absoluteLinkURL() can be null when the
user is long pressing on an image.

[dcheng, 2016/08/29 21:10:03]

As discussed offline, I think we can just check HitTestResult::URLElement().

[hush (inactive), 2016/08/29 21:14:53]

Done.

+
+    if (!hitTestContainsLinks && m_frame->eventHandler().handleDragDropIfPossible(targetedEvent)) {
         m_longTapShouldInvokeContextMenu = true;
         return WebInputEventResult::HandledSystem;
     }
-    IntPoint hitTestPoint = m_frame->view()->rootFrameToContents(gestureEvent.position());
-    HitTestResult result = m_frame->eventHandler().hitTestResultAtPoint(hitTestPoint);
-    if (m_selectionController->handleGestureLongPress(gestureEvent, result)) {
+
+    if (m_selectionController->handleGestureLongPress(gestureEvent, hitTestResult)) {
         m_frame->eventHandler().focusDocumentView();
         return WebInputEventResult::HandledSystem;
     }